Both the ideas in Irish's post ... and the tidbits in the first Snopes article were interesting. Probably the big point in Snopes (I gathered) is that the savings are not likely to be significant for the consumer over an extended period of time.

The other article about not buying from "X" brand is also good. Let's face, the only real way to put a crimp in oil company profits is for overall consumption to go down. Selective boycotts just won't have any meaningful impact (even if you could get "300 million" people to go along with the idea).